Brake mechanism for automotive vehicles



Jan' f3 193,1- c. s. BRAGG ET AL I 1,788,378

BRAKE MECHANISM FOR AUTOMOTIVE VEHICLES original Filed oct'. s, 1925 Y 2 sheets-sheet 2 Patented Jan. 13, 1931 UNITED STATES PATENroFFlcE l I i CALEB S. BRAGG, OF PALM BEACH, FLORIDA, AND VICTOR W. KLIESRATH, PORT WASHINGTON, NEW YORK, ASSIGNORS TO BRAGG-KLIESRATH CORPORATION, OF

LONG ISLAND CITY, NEW YORK, A CORPORATION OF NEW YORK BRAKE MECHANISM FOR AUTOMOTIVE` VEHICLES Application filed October 3, 1925, Serial ()ur invention consistsin the novel features hereinafter described, reference being nad to the accompanying drawings which show one embodiment of our invention, selected by us for purposes of illustration, and the said invention is fully disclosed in the following description and claims.

Our present invention is an improved power actuator especially advantageous for .iperaling brake vmechanism of automotive vehicles, and conveniently operated from the intake manifold, 'or suction passage, of the internal combustion engine which propels the vehicle, although it may be employed for other purposes, as for operating steering or other mechanism for automotive vehicles operatiug on land, on or in water or in the air.v

ln operating a power actuator requiring a very considerable amount sirahle to keep the size or diameter of the aetuator cylinder or cylinders as small as possible to economize space and weight and it is highly important where such actuators are operated by atmospheric pressure working against a partialvacuum obtained by a f-oi'ineetion with the suction passage of the internal combustion engine, that the smallest lpianlfities of air possible be withdrawn from ilus actuator and discharged into the vsaid .nu-.tion passage, in order that the proper proportions of air and fuel in the mixture passingl to thel engine shall not be materially altered. The proper operation ofan internal combustion engine requires the supply of explosive charges of pre-determined proportions of air and fuel, regulated as to quantity by the usual throttle valve, and the admission ol' la rge quantities()fair into the suction passage is naturally atlemled-by the danger ofv altering the proportions of air and fuel in the mixture to such an extent as to stall the engine` il' idling. or with its proper operation.

ln carrying out our present invention, we propose. to employ a plurality of actuator cylinders, and pistons, preferably two,'arrangedv co-a.;ial ly, and having their pistons connected for Joint operation, both cylinders being closed at both.- ends,

being provided with Areversing valve mechaof power, it is de! otherwise interferiu` 'T stallation of our improved power actuator 1n connection with an automotive vehicle for and one cylinder only No. 60,172. Renewed January. 17, 1928.

and to-admit atmospheric air on one side orface of each piston to effect the power applying effect of the actuator, (as the application of brakes) while on the return stroke the reversing valve mechanism admits atmospheric air on the opposite side or face o-f one piston only, (as to effect the release of the brakes) and maintains the other mersed in vacua. By this construction the diameters of the cylinders and pistons can be kept down, while providing the necessary power, sulicient for example to apply the brakes of large trucks, busses, and the like, while on the power applying stroke practically no air will be discharged into the intake manifold of the engine, and while on the return stroke the air admitted to both cylin-y ders for the power applying stroke will be exhausted and discharged into the manifold, after, the pistons return to the off, or normal position, the air admitted to one cylinder only (or to less than all'the cylinders, if

morefthan two are employed) will be eX- hausted, thus reducing very considerably the quantity of airwhich would otherwlse be admitted to the manifold, and assisting in avoiding the danger of interfering with'th'e carburetion and stalling of the motor 1f ldlmg.

piston or pistons im-` The admission of atmospheric airto a 'single' cylinder would ordinarily be more than ample for insuring the release of brakes, and the return of the piston or pistons ofthe other cylinder or cylinders to the off or normal position, which piston or pistons beapplying the brakes thereof.

Fig. 2 is an enlarged sectional view of the power actuator detached.

Fig. 3 is a' sectional view of the main or valved actuator cvlinder and piston, drawn to a still larger scale.

Fig. 4 is an enlarged sectional view of the .reversing valve mechanism.

Fig. 5 is a similar view of the co-axial valveless actuator cylinder and piston. In -the drawings vwe have shown anembodiment of our invention including a main actuator, an auxiliary actuator, the main actuator being provided with reversing valve mechanism for controlling both actuators as hereinafter described.

As shown. in Figs. 2, 3 and `4, the main actuator comprises a cylinder, 1, provided with heads, 2, 2', and a double acting piston, 3, to the hubof which are attached oppositely extending hollow. piston rods, 4 and 5, projecting through' suitable stalling boxes i 1n the heads, 2, 2i The hub', 10', of 'the piston is provided with reversing valveinecha- .nism designed tocontrol both actuators, one

form of which is shown herewith,` and which in this :instance is constructed as follows, al-

though the particular details Aoffv this valve mechanism are notgclaimedherein. and do not form part of our present invention. The piston hu is provided with valvechambers, 11 and 12, each provided with oppositely disposed conical -valve seats, indicated at 13,

14, 15 and 16, res ctively, to receive conical valves, 40, 41, an' 42, 43. Between the valve chambers is located a suction chamber, 17 w1th which the valve chambersv communicate by openings controlled by thevalves, 42 and 41. Atmospheric air may be admitted to the valve chamber, 11, through apertures, 4.", at the outer end 'of the piston rod, 4, under the control of valve 40, and likewise atmospheric air may be'admitted to valve chamber, 12, through apertures, 5, in the piston. rod.- 5. under the controlA of valve, 43.v

20 represents ja valve actuating` sleeve which extends through the hollow piston rods, 4 and' 5, the piston hub and the valves, 40, 41, 42' and 43., The valvesv are provided with Pvielding:retractng means tending to seat them andywith means for'sealing the apertures in the valves through which the sleeve, 20` passes. We prefer to make the valves of molded rubber and to construct them so that they fit air tight around the sleeve, while permitting thesleeve to move through the vcentral apertures in the valves. We also prefer to employ annular lspring retracting devices indicated at. 50, loosely engaging the sleeve, 20, and interposcd'between the oppositely disposed valves, 40,41.

\ and 42. 43. The valve actuating sleeve. 20, is

provided with collars, 40, 41", v42'. 43,v Sel cured thereto by spring rings` or othei'wise,

v4tion chamber, i17, and ,e

for `engaging the respective valves in .andirection to open them. Thecollars'. -41ffand '-142," are so arranged as to holdbothvalvesgf. 41'^and"`42 their seats when 'thepis'to is in owfor normal position, thereby' esa, tweenthesuc -Pv tablishing 'communic'jin V89., and a stop, 88.

The auxiliary actuator comprises a cylinsides of the piston, through-the valve cliambers, 11 and 12, and ports,"34 andv 35, connecting said chambers respectively withthe cylinder, the orts, 34, beinglocated on one side of the lston and the ports, 35, being locatedon tlie opposite sideof the piston. The valvel actuating sleeve, 20, is provided with apertures, 21, communicating with thevvacuum or suction chamber, 17, and adjacent to said apertures we provide the sleeve with a plug or partition, 22. The other end of the sleeve, 2A), is connected with a suitable sourceof-suction', as the'intake manifoldof an internal combustion engine, by a suction pipe, 62, a portion of which is lexibleto accommodate the longitudinal movements. of

the sleeve, and said sleeve is also provided with means, as a' perforated lug, 23, for connectingitwithanoperator operated part. In

this instance We have shown it in Fig. 1, connected byl a link, 85, with a pivoted foot lever, 88, provided with a retracting spring,

tween the. adjacent heads, 2 and 102, as. shown, but we do not-1imit ourselves to `this construction.` e y The auxiliary piston` is"l referably provided with a hollow hub, 1 0, to which are secured hollow piston rods, 104-and 105, extending through stuilin boxesin theo posite heads. .Thepiston ro 104,isdirect y connectedwith thehollow pistonrod, 5, of the main actuator, inth'is instance by a screw collar, ,106, into which the end-of the valve `actuating sleeve preferably projects. As will be seen, there is a certain-amount of lost motion. between the valve actuating sleeve and the main actuator` iston, suicient toeperate the` Vreversing va ve mechanism, and it is desirable to' linut this lostfmotion'n order that' the mainsactuator iston and the arts vconnected Atherewith,inc uding the auxi vlary actuator piston, -r and the brake E1. mechanism, may bel'positively actuated bythe operator y' operated part onffailu're of power, flor. to enable'thevoperator to add his physical'fpower to that exerted by, the actuators,lwhen deaired.` "Itisconhvenient to accomplish-,this by .providing the` valve. actuating sleeve, 20, wit

a collar, 24, within the serewconnecting collar. 106, between internal annular flanges, 106* :g and 106?, as .clearly shown 'in 2 and 8. l

It has been stated that when the parts are inthe normal or off positiomthe main actuator cylinder is connected with the suction chamber and intake manifold, so that the mainpiston is immersed in vacua. The same is truen of the auxiliary piston and to this end, we prefer to connect the auxiliary cylinder, 101, at the rear of the piston, when in retracted position, (at the left in Fig. 2) with the corresponding portion of the main cylinder by a pipe or passage, 107, and to connect the opposite end of the auxiliary cylinder at the right in Fig. 2, directly with the suction pipe, 62, by a pipe or passage,.108, independently of the reversing valve mechanism. By this construction, it will be noted that while the reversing valve mechanism can admit atmospheric air or higher pressure iiuid in rear ofthe main and also the auxiliary piston, and on the 'forward side of the main piston, it cannot admit the higher pressure fluid, (atmospheric air) forward of the auxiliary piston, and consequently, no air will be with-v drawn therefrom after rariication is effected therein, and there is that much less air to be delivered into the intake manifold of the engme. v

The piston rod, 105, of the auxiliaryactu'ator is intended to transmit the. power of both actuators to the part to be actuated, in this case, and usually, the brake mechanism of an automotive vehicle. The power may be applied to the brakes in any desired manner. In the drawings, we have shown the piston rod, 105, connected with the main hydraulic piston, 203, of a hydraulic brake system, and

arranged in the ymain hydraulic cylinder, which is connected by piping, indicated at 210, with a plurality of brake applying cylinders, 211, provided with pistons, 212, connected in any usual or desired manner, with the brake mechanisms, 213, which may be of any usual or preferred construction. We have shown the lnain hydraulic cylinder providedl with a liquid reservoir. 214, for the nonconipressibleliquid (oil) employed in the hydraulic system. the reservoir being shown connected with the cylinder, 201, by a passage, 215, containing a check valve, 216, for

vfilling the system, and by a passage, 217, ad-

jacent kto the piston when in retracted position. for venting the system. The details of the hydraulic system, however, form no part of our present invention, but are covered by a separate application for Letters Patent of the United States, filed by us on August 25th,

1925, and given Serial No. 51,300 and they will not be more particularly described, nor claimed herein. n

The hydraulic cylinder, 201, is provided with breathing apertures, 218, in rear of piston, 203, and the hollow piston rod, 105,of the auxiliary actuator may be provided with apertures, establishing communication from the atmosphere through the lillw pis-V the main and auxiliary actuators are in re- V tracted position, and the valves, 41 and 42, are held off their seats, as shown in Figs. 2 and 3, by the stop, 88a, for the hollow valve sleeve, 20, and by the pistons coming to rest against the rear end plates of the cylinders. It follows, therefore, that the main actuator cylinder, 1will beexhausted on both sides of the piston, 3through ports, 34 and 35, and the auxiliary 'actuator cylinder will likewise be exhausted on both sides ofthe piston by means of pipes*v or passages, 107 and 108,` previously described. To apply the brakes, the operator will move the brake lever forward so as to move thevalve actuating sleeve in the direction of the arrow in Fig. 2, thereby seating the valve, 41, and further opening the valve. 42, and opening valve, 40. admitting atmospheric air into the main actuator cylinder, '1, in rear of the piston, 3, and

atmospheric air-also passes from the main actuator cylinder, 1,-to the auxiliary cylinder, 101, in rear of the piston, 103, through pipe, 107.l Both pistons, 3 and 103, therefore, move in the direction of the arrow in Fig. 2, thereby moving the main hydraulic pistony 203, and applying the brakes. Or the actuator piston may be operatively connected with the brake mechanism in any other de'- sired manner. As soon as the movement of the valve actuating sleeve stops, the piston, 3, will overtake it, thereby seating the valve, 40, and so shutting off the source of pressure, thus lpermitting the equalization of pressures on the various sides of alll pistons to hohl thc load of the applied brakes. If the load causes the piston, 3, to moveslightly with respect ,to

site to that indicated by the arrow'inFig. 2.

This effects the opening of the valve, 41, to

withdraw the air previously admitted to the rear of the pistons, 3 and 103, for the application of the brakes, thec1osing of valve, 42, and the opening of valve, 43. The latter admits air (or higherpressure fluid) -i'nto cylinder, 1, through port, or ports, 35, forward of piston, 3, (at the right in Figs. 2 and 3)- but no air is admitted to cylinder, 101, forward of they piston, 103, which becomes immersedin vacuum, by means of the pipe con- ,nections -The piston, 3, is returned by the air admitted through valve, 43,' to its normal come to rest, the valve actuating sleeve will' be arrested insuch position as 'to hold both valves, 41 and 42, cracked, thus permitting Within cylinder, l, the simultaneous equali zation of'pressures, and the withdrawal of the air admitted to saidcylinder, only,in effecting' the r'eturn'stroke. This reduces the amount of air to be exhausted and delivered to the manifold, practically one-half or more, and this smaller quantity of air can be dis tributed into the manifold -under the control of thenregulatingvalve, so as .not to Y,inter fere materially with they operation of itheengine.l We therefore obtain by` 'our invene' tion, greatly increased 'owerfroman actua-jl tor havingcylinders o comparatively small", diameter, without a corresponding increase r into the intake manifold so ra idly as to interfere with the operation oft e engneso as to stall the engine if idling.

The valve actuating sleeve may be arrested in position to hold valves, 41 and 42,' off of' 'their seats when the main actuator piston 1s 1n the off or normal position, by any suitable means, as by a stop, 88?, with which the ,foot lever, 88, may -be provided, as shown, or 1n any other desired way.

It will also" be seen that in case of :failure of power, the operator can apply his physical force .to the pistons, 3, 103'and 203, to-,a plyV the brakes, and may, if desired, add his p ysical force tothe force exerted by the. actuators,

by taking up the lost motion between the collar, 24, and thecollars, 106, and 106", so that actuation of the brake mechanism `may always beeected, even -should the power fail forany reason. l

What we claim and desire to secure byLet- 1. The combination of a main actuator,

comprising a cylinder, adouble acting piston therein, and means includingreversmg valve mechanism and connections theiifrom vto a source of suction and to' a source"`"of higher pressure iiuid, for establishing'v diierential pressures on opposite faces of the piston', said.

valve mechamsm beingconstructed toy hold said piston in a balanced condition in an interjacent position of said valve mechanism, an auxiliary actuator comprising a cylinder ,closed at both ends, and a piston therein, the portion of said cylinder on one face of the pis'- ton being connected to the corresponding portion of the main actuator cylinder, .and the portion ofthe -auxiliary actuator cylinder on the opposite face of the piston, having an outlet passage independent of said reversing valve mechanism, connected with the source of suction, and operative connections between the main and auxiliaryA pistons, whereby higher pressure fluid may be admitted to both cy indersv to eiect a power stroke and to one cylinder only, to effect the return stroke.

2. They combination of a main actuator, comprising a cylinder, a double acting piston therein, 'andmeans including'reversing valve mechanism and connectionstherefrom -to v a source of suction, and to 'a' source of higher pressure jiiuid, for establishingl differential pressures on o posite faces'of the piston, said valve mechanism being constructed to hold said pistonin a balanced condition in an interjacent position' of said valve mechanism, an auxiliary actuator` comprising a cylinder Closed at both ends and a piston therein, the portion of `said cylinder on one face of the piston being-connected lto the corresponding portion of the main actuator cylinder, and the p ortion of the auxiliary actuator c 'linder on the opposite face ofthe piston, outlet passage independent ofl said reversing valve-mechanism, connected with the source of suction, means for holding the reversing valve mechanism in position'tb connect the main actuator cylinder on bothfaces ofthe pistonwith the source of suction, when the main piston is in thefo or normal osition, and operative connections between t e mam aving an and auxiliary pistons, wherebj'both pistons Y are normally immersed in vacta,'and higherA pressure fiuid may be admitted on one side of eachpiston to effect a pow'ercstrokeg-and may be admitted onthev reversegface of thel mamactuator piston only, onvthe return stroke, to minimize the 'entity-fof higher pressure. fluid exhaustedl gbythe'i' suction source. '3. -The combination hicle, provided with an nternalf-iombuation engine, and brake-mechanism offs main actuator, comprising a cylinder, a; double acting piston therein, and reversing valve mechanism, a suction pipeconnecting said valve mechanism with the euction'passage of the engine, means for admitting higher pressure iuid to said valve mechanism, said valve mechanism being constructed to connect the in an; automtiv'e vemam actuator cylinder with the said suction passage on both sides of the piston when the piston is in oil or normal position, an auxiliary valveless actuator, comprisingv a cylinder closed at both ends, a piston therein, operatively connected with the main actuator piston for joint movement therewith, a tubu'- lar connection between one end portion of the main actuator cylinder, and the corresponding end portion of the auxiliaryactuator cylinder, a tubular connection from the opposite end of the auxiliary actuator cylinder and sa1d suctlon passage, lndependent of sald reversing valve mechanism, and operative connections between the said pistons and the brake mechanisnn'.whereby both pistons will be immersed in vacua when in the olf position, and whereby on the power stroke to ap'- ply the brakes, higher pressure Huid will be admitted to the corresponding faces of both pistons, but on the return stroke higher pressure fluid will be admitted on the opposite face of the main actuator piston only.

4. The combination in an automotive vehicle, provided with an internal combustion engine, and brake mechanism of a main actuator, comprising al cylinder, a double acting piston therein, and reversing valve mechanism, a suction pipe connecting said Valve mechanism with the suction passage of the engine, means for admitting higher pressure Huid to said valve mechanism, said valve mechanism being constructed to connect the main actuator cylinder with the said suction passage on both sides of the piston, when the piston is in oft or normal position, an auxiliary valveless actuator comprising a cylinder closed at both ends, a piston therein, operatively connected with the main actuator piston for joint movement therewith, a tubular connection between one end portion of the main actuator cylinder, and the correspoiuling end portion ofthe auxiliary actuator cylinder, a tubular connection from the opposite end of the auxiliary actutator cylinder and said suction passage independent of said reversing valve mechanism, and operative connections between the said pistons and the brake mechanism, and an operator operated part for actuating said reversing valve mechanism, connected to said pistons by means permitting lost motion, whereby the physicial power of the operator may be transmitted to said pistons, when desired to add to the power of the actuators, or to operate the brake mechanism in case of failure of power.

5. The combination with a main power actuator comp-rising a cylinder, a double acting piston therein and reversing valve mechanism, a suction pipe connected with said valve mechanism, and means for admitting higher pressuretluid to said valve mechanism, of an auxiliary valveless actuator, comprising'a cylinderpermanently supported coaxially with the main actuator cylmder closed at both ends, andv provided with a piston connected with the main actuator piston,

a tubular connection from one end portion of the main cylinder to the corresponding end portion of the auxiliary cylinder, a suction pipe connected with the opposite end portion of the auxiliary cylinder,fimlcpcndcntly ot said reversing Vvalve mechamsm, operator operated means for controllmg said reversing valve mechanism, and operative connections extending from `said connected pistons and adapted to be connected with a part to he operated.

6. The combination with a main power actuator comprising a cylinder, a double acting piston therein, and reversing valve lucchani.sm, a suction pipe connected with said valve mechanism` and means for admitting higher pressure fluid to said valve mechanism, said valve mechanism :being constructed to connect the main actuator cylinder on both sides of the piston with the suction pipe, ot an auxiliary valveless actuator, comprising a cylinder closed at both ends, and a piston, co-axial with the main cylinder and piston, the main actuator piston being-provided with a piston rod connected with the auxiliary actuator piston, 'and one of said pistons being provided with means for connecting it with a part to be actuated, a tubular connection from the portion of said main actuator cylinder, on one side of the piston to the corresponding portion of the auxiliary actuator cylinder, the portion ot the latter cylinder'on the opposite side of the piston being connected to said suction pipe independently of the valve mechanism, and an operator operated part for controlling said reversing valve mechanism.

7. The combination with a Inain actuator, comprising a cylinder, a double acting` piston therein, and reversing valve mechanism located in said piston, a tubular suction passage connected with said valvel mechanism',

including a longitudinally movable valve actuating sleeve, hollow piston rods connected with said piston and extending through opposite ends of the cylinder, and providing means for admitting a higher pressure fluid to said valve mechanism, of an auxiliary valveless actuator comprising a cylinder closed'at bothcnds land a piston arranged co-axially with respect to the main actuator piston and cylinders, said cylinders being se'- cured rigidly with respect to each other, said auxiliary actuator piston being provided with pist-on rods yextending through opposite ends of the auxiliary actuator cylinder, one being rigidly secured to a piston rod of the main actuator and the other heilig4 provided with means for connecting it to a part to he actuated, a tubular passage connecting the main cylinder on one side of its piston with the corresponding ,portion of the auxiliary cylinder, and a tubular passage connecting the auxiliary cylinder on the opposite side n to said valve mechanism, of an auxiliary valveless actuator, comprising a cylinder closedl at both ends, and a piston arranged co-axially with respect to the main actuator piston and cylinders, said cylinders being secured rigldly with respect to each other, said auxiliary actuator 'piston being provided with piston rods extending through opposite ends of tl.1e auxiliary actuator cylinder, one belng rigidly secured to a piston rod of the main actuator and the other being provided with means for connecting it to a part to be actuated, a tubular passage connecting the main cylinder on'one side of its piston with the corresponding Dortinn of the auxiliary cylinder, and a tubular passageconnecting the auxiliary cylinder on the opposite side of its piston, with the suction passage, independently of the reversing valve mechanism, an operator operated part connected with said valve actuating sleeve, andv connections between said sleeve and one of said pistons, providin'gsuiiicient lost motion to permit of the operation of the reversing valve mechamsm.

9. The combination of a main actuator, comprising' a cylinder, a double acting piston therein, and means including reversing valve mechanism and connections therefrom to a source of suction and to a source of higher pressure fluid, for establishing differential pressures lon opposite faces of the piston,-

said valve mechanism being constructed to hold said piston in a balanced condition in an interjacent position of said valve mechanism, an auxiliary actuator comprising a cylinder, and a piston therein, theportion of said cylinder on one face of the piston being connected with the corresponding portion of the main actuator cylinder, and the portion of the auxiliary actuator cylinder on the opposite face of the piston, having an outlet 'passage independent of said reversing valve mechanism', connected `with the source of suction, whereby-higher pressure iuid may be admitted to both cylinders to effect the power stroke and withdrawn from both cylinders, and may be admitted to one cylinder only to eifect the return stroke thereof, and means for eiecting the return stroke of the. other piston without the admission of air to the cylinder thereof. Y A

10. The combination of a main actuator,

comprising a cylinder, a ldouble acting piston therein, and means including reversingvalve mechanism and connectionstherefrom to a source'of suction, and to a source of high-4 er pressure iiuid, for establishing differential vpressures on 'opposite faces of the piston,

lsaid valve mechanism being constructed -to hold said piston in a balanced condition in an interjacent position of said valve mechanism, an'auxiliary actuator comprising a vpiston with the source of suction,- When the main piston is in the oif or normal position, and means for. effecting the return stroke of the auxiliary piston without admitting higher pressure vfluid to the auxiliary cylinder, whereby both pistons are normally 1mi mersed in vacuumand higher pressure fluid may be admitted to both cylinders on one side of each piston to effect a power stroke, and withdrawn from both cylinders, and may be' admitted tothe main actuatorcylinder only on the reverse face of the main actuator piston on the returnstroke, to minimizethe uantity of higher pressure Vfluid,

exhausted y the suction source.

11'. The combination in an automotive vehicle provided withan internal combustion engine having a suction passage and brake mechanism, of a main actuator comprising a cylinder, a .double acting piston therein, and

reversing valve mechanism, means for connecting said cylinder with thesaid suction passage of the engine and with the atmosphere under the control of said reversing valve mechanism, said valve mechanism being constructed to hold said piston in a balanced condition in an interjacent position o'f said valvemechanism, an auxiliar actuator comprising'a cylinder closed at bot ends and a 'piston therein, the portion of the auxiliary cylinder on one face of 'fthe`=piston being connected-to the corres ondin ortion of with the source of suction vindependently of the valve mechanism for the main .,actuator,

connections between said pistons and'brake mechanism of the vehicle, and an operator operated part connected with the valve mechamsm for the main actuator, -whereby air -the main actuator cylin er, an t e portion actuator cylinder on the opposite face o the piston being connected may be admitted to both cylinders to simultaneously eect a power stroke of both pis tons to apply the brakes connected therewith,

and to the main cylinder only to eife'ct the release of the brake mechanism without admitting air to the auxiliary. actuator cylinder.

12. The combination in an automotive vehicle provided. with an internal combustion engine having asuction passage and brake mechanism, of a main actuator comprising a cylinder, a double acting piston therein, and reversing valve mechanism, means for connecting said cylinder with saidl suction passage of the engine and with the atmosphere under the control of said reversing valve mechanism, said valve mechanism being constructed to hold said piston in a balanced condition in an interjacent position of said valve mechanism, an auxiliary actuator comprising a cylinder closed at both ends and a v double piston therein, the portion of the auxiliary cylinder on one face of the piston being connected to the corresponding portion of the main actuator cylinder, and the portion of the auxiliary actuator cylinder on the opposite face of' the piston being connected with the source of suction independently of the valve mechanism for the main actuator, connections between said pistons and brake mechanism of the vehicle, an operator-operated part connected with the valve mechanism for the main actuator, the -main and auxiliary actuator pistons being positively connected for joint operation, whereby air vmay be admitted to both cylinders -to simultaneously effect a power stroke ofv both pistons to apply the brakes connected .therewith and to the main cylinder only to eect the return movement o both pistons and the brake mechanism connected therewith.

13. The combination in an automotive vehicle provided `with an internal combustion engine having a suction passage and brake mechanism, of a main actuator comprising a cylinder, a double acting piston therein, 'andreversing valve mechanism, means for connecting said cylinder with said suction passage/of the engine and with the atmosphere under the control of said reversing valve mechanism, said'valve mechanism being constructed to hold said piston in 'a balanced condition in an interjacent position of said valve mechanism, an auxiliary actuator comprising a cylinder closed at both ends and a double piston therein, `the portion of the auxiliary cylinder on one face of the piston being connected tothe corresponding p0rtion of the main actuator cylinder, andthe portion of the auxiliaryactuator cylinder on the opposite face of the piston being connected with the source of suction independently of the valve mechanism for the main actuator, connections between said pistons and brake mechanism of the vehicle, an operator operated part connected with the valve mechanism for the main actuator, and operative connections between said operator operated part and the main actuator piston providing lost motion sutlicient to insure the operation ofthe valve mechanisrmwhereby air may be admitted to both cylinders to simultaneously effect a power stroke of both pistons to apply the brakes connected therewith and to the main cylinder only to etii'ect the rclease of the brake mechanism withoutA admitt`n air to the auxiliary actuator cylinder, ang whereby the operator may add his physical force to the main actuator piston and operate the same by physical force alone in case of failure of power.

14. The combination in an automotive ve- -hicle provided with an internal combustion sage of the engine and with the atmosphere under the control of saidy reversing valve mechanism, 'said valve mechanism being constructed to hold said piston in a balanced condition in an interjac'ent position of said valve mechanism, an auxiliary actuator comprising a cylinder closed at both ends and a double piston therein, the portion-of the auxiliary cylinder on one face ofthe piston being connected to the corresponding ortion of the main actuator cylinder, and the portion of the auxiliary actuator cylinder on the opposite face of the plston being connected with the-source of suction independently of the valve mechanism for the main actuator, connections between said pistons and lbrake mechanism of the vehicle, an operator operated part connected with the valve mechaicc nism forthe main actuator, said pistons bethe return movement of both pistons and the brake mechanism connected therewith, and whereby the operator mayl add his physicalforce to both pistons and the brake mecha.-

nism connected therewith and may operate both istons and the brake mechanism connecte therewith by physical force alone in case of failure of power.

In testimony whereofwe aliix our signatures.

CALEB S. BRAGG. VICTOR WgKLIESRATH. 

